1. Field of the Invention
The invention relates to a roller conveyor with side wings extending out and spaced apart from each other wherein a series rollers are successively arranged between these side wings in the direction of conveyance. The rollers are rotatably supported on both sides at both ends by means of trunnions extending into the rollers on their face sides. These rollers are driven by a motor.
2. Description of the Prior Art
Generally, roller conveyors are equipped with drum drives. Drum drives are arranged within the tubular rollers of the conveyor, transmitting the driving motion to the respective roller by means of a non positive friction drive. These drum drives consist of a DC motor and a gearing. When the rollers are driven, the counter-torque is introduced into, and absorbed in one of the side wings of the conveyor via a square or hexagonal shaft. This shaft is hollow and allows a cable to extend through the hollow shaft from the outside and into the interior of the motor.
The advantage offered by such drum drives lies in that they are accommodated within the driven rollers in a space saving way. However, only motors with low capacities can be installed because of the limited diameter of the rollers having a clear inner width, for example, a width of only 50 mm. Furthermore, it is unfavorable to have only motors designed for 24 volts DC, that can be employed in most cases for safety reasons.
The object of the invention is to provide an improved roller conveyor wherein the drives can be installed without limitations of the diameter of the rollers and driving motors of any desired type and with any desired operating voltage.
This problem is solved wherein the roller conveyor is in driving connection via a transmission with a driving motor arranged on a side wing outside of the actual roller conveyor.
As opposed to the prior art, in the present invention, the driving motor is arranged outside of the driven roller on the side wing located on the driving side. This eliminates the limitation of the structural size of the driving motor posed in the prior art by the diameter of the rollers, and the limitation of the motor capacity conditioned by the former limitation. It is now possible by virtue of the invention to install driving motors of any desired type and size on the outer side of the side wing and to transmit their driving output via an interconnected gearing or transmission to the roller to be driven.
According to a further development of the invention, the side wing on the driving side is designed as a box section which is open on the side facing away from the rollers, wherein the driving motor and the gearing are received within the box like section so that they do not project laterally from the roller conveyor.
The open side of the side wing designed in the form of a box-like section is usefully closed by an external cover, and the driving motor and the gearing are accordingly accommodated in this further developed embodiment in a space, encapsulated against the outside.
A particularly compact type of design is obtained if, according to another further development of the invention, the driving motor and the gearing are combined in a geared motor. This motor is suitably mounted on the side of the lateral wing of the roller conveyor facing away from the rollers.
According to another development of the invention, the trunnion supporting the roller on the driving side may be an output shaft of the gearing protruding into the roller at the face end. These shafts are connected with torsional strength with the roller and extend through a recess in a side wing.
Therefore, in a further developed embodiment, the output shaft of the gearing assumes the support of the driven roller on the driving side. In this case, conventional roller conveyors require a special bearing arranged, on the side of the lateral wing on the driving side pointing at the roller.
According to another important embodiment of the invention, the driving connection between the gearing and the motor-driven roller comprises a coupling compensating an angular or axial error.
This type coupling contains a sleeve of the coupling wherein it has torsional and axial strength in the roller at the face end on the driving side. It is also provided with an inner toothing as well as a hub component. This hub component is connected with torsional and axial strength with the trunnion on the driving side. For example, the output shaft of the gearing has an outer toothing positively engaging the inner toothing of the sleeve of the coupling.
This type coupling permits replacement of the driven roller, when needed, so that it doesn""t require dismantling and reinstallation of the transmission gearing or driving motor. This coupling provides for a particularly precise support of the roller on the driving side if the hub component of the coupling is received on the output shaft projecting from the gearing.
The outer sleeve of the coupling may be connected with the driven roller with torsional and axial strength in any desired way. However, it was found that it is particularly simple and inexpensive if the sleeve of the coupling is pressed into the tubular roller at the face end.
To compensate against any alignment flaws between the trunnion of the driving side and rotational axle of the driven roller, the outer toothing of the coupling""s hub component is preferably cambered or spherical.
Furthermore, the axial expanse of the hub component should be smaller than the axial expanse of the sleeve of the coupling so that a certain compensation of axial errors is possible within preset limits.
With the roller conveyor, the rollers not directly driven by the motor are in driving connection with the roller directly driven by the motor via loop drives. To drive via these loops, each of these rollers has two circumferential corrugations which are spaced apart from each other axially for accommodating round or toothed belts or similar known driving means producing a rotational connection in each case with the adjacent roller. This rotational connection is located on the side facing away from the drive.
The invention provides a roller conveyor in which commercially known motors and transmissions and particularly geared motors can be employed, so that there can be nearly unrestricted variations in speed (rpm""s) and torque. Since the drive is arranged outside of the actual roller conveyor track, the conveyor can be used in sterilized or wet rooms. Furthermore, arranging the drive off-side the actual roller conveyor track permits a high safety standard. This is because the motor and transmission gearing is encapsulated and there is protected installation of the electric feed connections.
The driven shaft transmits torque to the driven roller via a compensating coupling which allows the roller to swing in all directions. This is in addition to the positive transmission of the force within preset limits. In this case, the installation errors or flaws are directly compensated. Furthermore, the use of such a coupling permits simple dismantling and reinstallation of the driven roller without having to remove the driving motor and the gearing for such a purpose.